Reservoirs and Transmission Flashcards
Disease transmission is the result of the interaction between what three things? (remember the triangle diagram)
Host
Agent
Environment
What outbreak is John Snow associated with containing?
Cholera - 1849
He located the water source that was too close to sewage and making people sick
Who was the scientist to first isolate anthrax?
Robert Koch - Published his findiing s in 1876
This was the beginning of modern “germ theory”
Who was the first scientist to discover dz transmission via vectors? What dz and what vectors?
1897 - Ronald Ross discovered that malaria is transmitted by mosquitoes
T/F: To be considered a reservoir, it must be a living organism
FALSE
Environments like lakes, soil etc can be reservoirs
T/F: Every exposure of the same pathogenic agent will be similar
False
Every exposure is unique
Is it more common for a pathogenic agent to infect multiple hosts in multiple environments or to stay secluded to one host in the same environment?
Often there are multiple hosts, with multiple agents, in multiple environments
What two levels can you evaluate the “means of escape” of an agent?
Individual level - like escape from the host; sneezing, coughing, urine etc
Ecological level - if an agent is spread via a natural event like a flood, deforestation, or something else that causes a spill over from that certain reservoir
What is a reservoir?
Habitat which an infectious agent normally lives, grows, and multiples
What are the three requirements to be considered a reservoir?
- it is naturally infected with the pathogen
- It can contain the pathogen over time (often very long periods of time)
- Ability to transmit disease to a new host
T/F: All sick animals are reservoirs
FALSE
What are some modes of vertical transmission?
Transmission from a reservoir host to its offspring
Can be congenital (crosses the placenta, infects eggs, etc)
Perinatal - transfer during parturition, via colostrum
What are some examples of horizontal transmission?
Horizontal transmission = from the reservoir to a new host
Direct - bite, contact, projection, airbone, etc
Indirect - fomites, insect vectors, vehicles
What is the difference between vectors and vehicles?
Vectors are living (can be mechanical or biological)
Vehicles are inanimate objects that get contaminated
Who or what is the Index Patient?
The index patient is the first infected patient to bring attention of the disease to the authorities
This is not necessarily patient zero or the first to be infected with the disease (there may be many patients that were infected and died, before knowledge of the disease)
